1. Field of the Invention
The present invention concerns a cassette acceptance device with the capability to recognize the state of the cover of the cassette opening or bay in a printing mail processing apparatus or a similar printing billing or mail processing apparatus.
2. Description of the Prior Art
Conventional thermotransfer franking machines of the type T1000 and Optimal commercially available from Francotyp Postalia & Co. KG do not have piracy protection for consumable material, i.e. an ink ribbon in a cassette. By means of an encoder, a microprocessor controller allows an ink ribbon conveyor to establish that an encoder disc is fastened on the same axle as a friction wheel, and the latter is likewise rotated. When the flap of the cassette bay is opened, a simple mechanism is activated and the friction wheel is raised from the ink ribbon of the cassette, which allows the cassette to be removed without causing damage. The operation of the machine is interrupted given a faulty ink ribbon transport.
The arrangement of a switch on the security housing of a franking machine is known from EP 1300807 A2; for different reasons, namely for protection for an operator so that if fingers of the operator are inserted into an opening of the franking machine, such as Ultimail®, also available from Francotyp Postalia & Co. KG, they are not crushed by the transverse movement of the printing carriage. This solution is only suitable for inkjet printing franking machines, particularly for exchange of ink cartridges via the opening that can be sealed by a flap. The flap is equipped with a stop that, upon opening of the flap, activates a switch inside the security housing, causing current supply to a motor of the transverse movement mechanism of the printing module to be interrupted. Adoption of this solution for thermotransfer franking machines with ink ribbon cassettes is not possible without difficulty since there no movement of the printing module nor an exchange of an ink cartridge. Moreover, recently mail carrier regulating authorities have begun to require a higher printing quality that is supported by piracy protection measures from the franking machine manufacturer (such as a chip applied on the consumable material).
DE 199 58 946 A1 discloses a thermotransfer franking machine with a microcomputer to which a contact or sensors is/are applied in order to indirectly establish the presence of exchanged consumable material based on a physical characteristic by means of an evaluation (implemented by the microprocessor) of measured sensor data and stored operating data. If a chip with identifying data is not arranged on the cassette, a chip card (provided for this purpose) must then be inserted into a slot of a chip card reader in order to read the identifying data. The exchange is thus permitted only some time later. Moreover, exactly where the sensors are arranged and which of these are used for evaluation is dependent on the franking machine type, because usually already-present sensors are used that do not specifically detect an exchange of consumable material.
A detector is known from DE 199 58 941 A1 that also reliably detects the removal or exchange of consumable material when the apparatus is deactivated and is not supplied with system voltage. For this purpose, the detector uses a typical lithium battery that supplies a memory with a memory-retention voltage. There is no discussion, however, as to exactly where the sensor is arranged relative to the cassette. According to one variant, piracy protection is possible for thermotransfer cassettes in the form of an electronically-programmable chip, but this presumes a precise alignment of the cassette with the chip relative to a reading unit (chip reader) and the application of a contact force on order to securely read the data. Given the use of a chip for the purpose of piracy protection, in operation an electrical voltage is applied across the chip. This document does not address preventing removal or circumvention of the cassette during the operating state, such that access to the activated reading unit is possible. Such an access would at least lead to operational interferences or to manipulation or even to destruction of the chip.